If you’re getting a PostgreSQL error that reads “op ANY/ALL (array) requires array on right side” it’s probably because you’re passing a non array to the ANY() or ALL() construct.
These constructs require an array to be included in the parentheses, and so passing a non array returns an error.
To fix this issue, be sure to pass an array when using these functions.
Continue readingIn PostgreSQL, the trim() function can be used to trim both sides, or a specified side, of a string. We can trim blank spaces or we can specify certain characters to trim.
It removes the longest string containing only characters from the ones we specify. If we don’t specify any characters, then it removes blank spaces.
Continue readingWe can use the array_remove() function in PostgreSQL to remove elements from an array.
We pass two arguments when calling the function; the first is the array and the second argument is the element to remove. All occurrences of the specified element are removed.
The function returns an identical array, but without the specified element/s.
Continue readingBy default, PostgreSQL arrays are one-based. That means that the numbering starts at subscript 1 and increments with each element in the array. However, we can change this so that the array starts at a different subscript.
Continue readingIf you’re getting a PostgreSQL error that reads “function generate_subscripts(numeric, integer) does not exist“, it’s probably because your first argument is not an array. This specific error message implies that the first argument is a numeric value, but we’d get a similar error when passing an integer.
The first argument for this function must be an array.
To fix this error, be sure that your first argument to generate_subscripts() is an array.
In PostgreSQL, we can use the array_cat() function to concatenate two arrays.
We pass both arrays as arguments when we call the function.
Continue readingIf you’re getting a PostgreSQL error that reads “searching for elements in multidimensional arrays is not supported“, it’s probably because you’re trying to perform an operation against a multi dimensional array when that operation only supports one dimensional arrays.
To fix this issue, perform the operation against a one dimensional array instead. You may be able to do this by applying the unnest() function against the multi dimensional array.
PostgreSQL has a function called btrim() that we can use to trim both sides of a string. We can trim blank spaces or we can specify certain characters to trim.
It removes the longest string containing only characters from the ones we specify. If we don’t specify any characters, then it removes blank spaces from both sides.
We provide the string as the first argument, and the (optional) characters as the second.
Continue readingIn PostgreSQL, we have many ways to retrieve data from arrays. One way is to specifically reference its subscript or a range of subscripts. Another way is to search through the array’s contents for the value we want.
By doing a search, I mean we could do things like filter the query with a WHERE clause, so that we only return rows that contain an array that has an element with a certain value.
In PostgreSQL, the array_prepend() function prepends an element to the start of an array.
The first argument is the element to prepend, and the second argument is the array.
Continue reading